The present invention relates to a process cartridge and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable.
Here, the term xe2x80x9celectrophotographic image forming apparatusxe2x80x9d refers to the an apparatus that forms images on recording materials using an electrophotographic-image-formation-type process.
Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (a laser beam printer, an LED printer or the like), a facsimile device and a word processor.
The process cartridge is a unit containing charging means, cleaning means and an electrophotographic photosensitive member as a unit, wherein the cartridge is detachably mountable to the main assembly of the image forming apparatus.
It may contain the cleaning means and electrophotographic photosensitive member as a unit.
Such a process cartridge is advantageous in that maintenance of the apparatus is easy since the exchange of the process cartridge is, in effect, the maintenance.
An image forming apparatus using the electrophotographic image forming process employs such a process cartridge.
The process cartridge type is advantageous in that maintenance of the apparatus can be in effect carried out by the users, and therefore, the operativity is remarkably improved.
For this reason, the process cartridge type is widely used in the field of the image forming apparatus.
With the extension of the lifetime of the electrophotographic photosensitive member (increase of printable number of sheets), it is desired that developing means, which must be supplied with power, is made independent from the other parts including the electrophotographic photosensitive member, the charging means and the cleaning means to permit longer use without losing the easy mounting-and-demounting of the unit to the main assembly of the apparatus.
The residual developer (toner) resulting from the cleaning operation in the process cartridge is stored in the cleaner container having a volume sufficient to accommodate all the residual toner generated during the lifetime of the electrophotographic photosensitive member, and is removed by exchange of the process cartridge.
In the cleaning container, there are provided partition walls for dividing the cleaning container into the electrophotographic photosensitive member side and the rear side of the container, an opening provided in the partition wall, and developer feeding means including rotatable blades for feeding the developer in such a part of the cleaning container closer to the electrophotographic photosensitive member.
With the extension of the service life of the electrophotographic photosensitive member, the residual toner accommodating portion of the process cartridge has to accommodate the residual toner after the development and transfer operation of the plurality of the developing devices, and therefore, the capacity thereof has to be relatively larger.
In view of this, the following two alternatives are considered for the mounting and demounting of the process cartridge in terms of the positional relation relative to the other units.
(1) A hole portion is formed in a side plate portion of the main assembly of the image forming apparatus, and the process cartridge is mounted and demounted in a horizontal direction which is substantially parallel with a direction of the generating line of the electrophotographic photosensitive member.
(2) A movable member, which is drawable or retractable in the horizontal direction and in the perpendicular direction relative to the direction of the generating line of the electrophotographic photosensitive member, is provided, and the process cartridge is mounted to or demounted from the movable member, and the movable member is mounted to or demounted from the main assembly of the image forming apparatus.
By doing so, the process cartridge can be smoothly mounted to or demounted from the main assembly of the apparatus.
Accordingly, it is a principal object of the present invention to provide a process cartridge and an image forming apparatus having a movable member in which the process cartridge can be smoothly mounted to or demounted from the movable member with a simple structure.
It is another object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus wherein the process cartridge can be assuredly positioned relative to the movable member and the image forming apparatus with a simple structure.
It is a further object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus, wherein the process cartridge can be smoothly mounted to and demounted from the movable member, and can be smoothly and assuredly mounted to and demounted from the main assembly of the image forming apparatus.
According to an aspect of the present invention, there is provided a process cartridge detachably mountable to a main assembly of an image forming apparatus, wherein the process cartridge is mounted to or demounted from a movable member, which is retractable in a horizontal direction, to mount the process cartridge to the main assembly or to demount the process cartridge from the main assembly, comprising: an electrophotographic photosensitive member; a cleaning member for removing toner from the electrophotographic photosensitive member; a toner feeding portion for feeding by a toner feeding member toner removed from the electrophotographic photosensitive member by the cleaning member; a cartridge frame supporting at least the electrophotographic photosensitive member; a first projection projecting outwardly substantially coaxially with the electrophotographic photosensitive member, provided on one end surface of the cartridge frame, as seen in a mounting direction when the process cartridge is mounted to the main assembly of the image forming apparatus; a third projection projecting outwardly at a position upstream of the first projection with respect to the mounting direction; a second projection projected outwardly substantially coaxially with the first projection, provided on the other end surface; a fourth projection projected outwardly substantially coaxially with the third projection; wherein centers of the first and second projections are placed at predetermined positions in the main assembly of the image forming apparatus; wherein the third and fourth projections are placed at predetermined circumferential positions about the center; wherein the first, second, third and fourth projections function as guiding members when the process cartridge is mounted to or demounted from the movable member.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.